MPTCP Sub-session Establishment via NAT and Firewall Traversal

The patent applies preliminary action by having the initiating device collect information about NAT devices and firewalls before establishing MPTCP connections. The device proactively creates appropriate entries in these network security devices and obtains reliable external IP addresses and port numbers in advance, ensuring that connection establishment can proceed successfully despite the presence of NAT and firewall configurations.

The patent uses an intermediary approach by introducing a relay mechanism where the initiating device acts as an intermediary between the communicating devices. It collects NAT and firewall information, manages the creation of appropriate entries, and coordinates the exchange of reliable address and port number information between the two communicating devices, thereby mediating the connection establishment process through environments with NAT and firewalls.

The patent applies feedback by implementing a mechanism where communicating devices continuously exchange information about their available IP addresses and port numbers through TCP options. When a device's network conditions change (IP address change, interface unavailability), it notifies the other device through feedback messages, allowing the receiving device to update its connection information and maintain stable communication despite dynamic network changes.

The patent embodies dynamics by enabling TCP connections to adapt dynamically to changing network conditions. The connection information (IP addresses, port numbers) is not fixed but can be updated during the connection lifetime through the exchange of TCP options. This allows the connection to remain stable while adapting to dynamic changes in network topology, interface availability, and address assignments.

The patent applies universality by enabling a single TCP connection to serve multiple functions across different networks through the use of multiple IP addresses and port numbers. The MPTCP connection can dynamically utilize any of the assigned IP addresses and ports depending on network conditions, making the connection management system universal rather than requiring separate TCP connections for each network interface.

The patent implements self-service by enabling MPTCP terminals to autonomously manage their own multiple IP addresses and port numbers. The devices automatically collect NAT and firewall information, create appropriate entries, exchange connection information through TCP options, and maintain the connection without requiring external intervention, thereby reducing overall system complexity despite the multi-address configuration.